Simplex Algorithm Two Phase Method Calculator

Enter objective coefficients, constraints, and optimization direction safely. Trace Phase I and Phase II tableaux. Export clear reports for simplex decisions and feasibility checks.

Calculator Input

Write one constraint per line. Example: 1, 1 >= 4. Coefficients follow x1, x2, and so on.

Example Data Table

Model Part Input Purpose
Objective 3, 5 Use 3x1 + 5x2.
Constraint 1 1, 1 >= 4 Adds surplus and artificial variables.
Constraint 2 1, 3 <= 9 Adds a slack variable.
Constraint 3 1, 0 = 2 Adds an artificial variable.

Formula Used

Phase I: Minimize W = a1 + a2 + ... + ak. This script solves the equivalent maximization of -W.

Reduced cost: Cj - Zj = cj - cB B-1Aj. A positive value can improve a maximization tableau.

Ratio test: θ = bi / aij, where aij is positive. The smallest nonnegative ratio leaves the basis.

Final objective: Z = c1x1 + c2x2 + ... + cnxn. The calculator reports the original objective direction.

How to Use This Calculator

  1. Choose maximize or minimize.
  2. Enter the number of decision variables.
  3. Type objective coefficients in order.
  4. Enter each constraint on a new line.
  5. Use <=, >=, or = between coefficients and the right side.
  6. Press Calculate to view Phase I, Phase II, and the optimum.
  7. Use CSV for spreadsheet work or PDF for a saved report.

About the Two Phase Simplex Method

The two phase simplex method solves linear programming models that need artificial variables. It is useful when constraints include greater than or equal signs, equalities, or awkward starting points. Phase I searches for a feasible basic solution. Phase II uses that feasible basis to improve the real objective.

Why This Calculator Helps

Manual tableau work can become slow. Each pivot must be selected with care. A single ratio error may change the answer. This calculator builds the standard form, adds slack variables, adds surplus variables, and adds artificial variables where needed. It then runs Phase I and Phase II with clear rows, reduced costs, and final variable values.

Practical Use Cases

Students can check homework steps. Teachers can prepare worked examples. Analysts can test small production, blending, diet, transport, and scheduling models. The calculator assumes nonnegative decision variables. It also expects every constraint to be written with coefficients in the same variable order.

Reading the Output

The report shows whether the model is feasible, optimal, infeasible, or unbounded. Phase I should end with an artificial objective value of zero. If it does not, the original model has no feasible region. In Phase II, positive reduced costs show possible improvement for maximization. The ratio test chooses the leaving row.

Good Modeling Tips

Enter clean coefficients. Use commas between values. Place one constraint on each line. Check that the right hand side is correct. Negative right hand sides are normalized before the algorithm starts. This makes the initial tableau easier to read.

Accuracy Notes

The calculator uses decimal arithmetic and a small tolerance. Very large coefficients or nearly parallel constraints can produce roundoff effects. For sensitive industrial models, confirm the final plan with professional optimization software. Still, this page is a practical learning tool for many classroom and planning problems.

Exporting Results

Use the CSV button for spreadsheet review. Use the PDF button to print or save the visible report. Keep the exported file with your assumptions, because linear programming answers depend strongly on the model you entered. Scenario testing is also useful. Change one resource limit, cost, or profit at a time. Then compare the objective value and active constraints carefully before making final decisions.

FAQs

What is the two phase simplex method?

It is a simplex approach for models that lack an obvious starting feasible basis. Phase I finds feasibility with artificial variables. Phase II optimizes the real objective.

When should I use Phase I?

Use it when constraints include greater than or equal signs, equality signs, or any case where a clean initial basic solution is not visible.

What input format should constraints use?

Enter coefficients first, then the sign, then the right side. For example, write 2, 3 >= 12 for 2x1 + 3x2 >= 12.

Can this calculator solve minimization problems?

Yes. The script converts the minimization objective into an equivalent internal maximization step, then reports the original objective value.

What does infeasible mean?

Infeasible means no decision variable values satisfy all constraints at the same time. Phase I detects this through remaining artificial value.

What does unbounded mean?

Unbounded means the objective can keep improving without a limiting leaving row. The model may need another realistic constraint.

Are negative right hand sides allowed?

Yes. The calculator normalizes negative right hand sides by multiplying the full constraint by negative one and flipping the inequality direction.

Can I export the result?

Yes. Use the CSV button for spreadsheet data. Use the PDF button to open the print dialog and save the report.

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